The present disclosure relates to a sheet transport mechanism for transporting a recording medium of sheet form, such as paper or the like, in an image forming device such as a fax machine, copier, printer, or the like, and to an image forming device provided with the same.
In image forming devices such as fax machines, copiers, printers, and the like, sheet transport mechanisms in which pairs of transport rollers, composed of pairs of rollers pressed into contact with one another, rotate in order to transport a sheet while pinched in the nip of the pair of rollers, are widely employed as means for transporting sheets (recording media) such as paper, cloth, OHP sheets, and the like.
In this sort of sheet transport mechanism, one of the rollers constituting the transport roller pair is pressed into contact against the other roller at a predetermined pressure, by means of a tension spring, compression spring, or the like. In the past, the typical method for doing so was to furnish individual springs at left and right in the axial direction of the transport roller pair, and to press one roller against the other roller.
However, when individual springs are furnished at left and right in the axial direction, variability in the dimensions of the springs may cause the pressing force on the transport roller pair to differ between left and right in the axial direction. As a result, the transporting force acting on the sheet may be uneven between left and right in the axial direction, causing the sheet to experience oblique motion.